1. Field of the Invention
The present disclosure relates to an in-pipe inspection robot for inspecting a pipe.
2. Description of the Related Art
Generally, an in-pipe inspection robot is provided to inspect the pipelines installed in a nuclear power plant, a thermoelectric power plant or chemical plants where human access is restricted for safety reason, performing a role of improving the safety of the facilities by moving in the pipelines and closely inspecting foreign materials clogging the pipes, cracks occurring in the pipes or micro-defects in the pipes.
The in-pipe inspection robots such as small wheeled electric vehicles are known. However, these robots have problems of unsatisfactory performance of the desired action, for reason such as wheels sliding on pipes. Accordingly, these days, the technology of in-pipe inspection robot employing a linear actuator as a driving means has been developed.
Particularly, a rack-and-pinion system or a ball screw mechanism is known as the linear actuator. The rack-and-pinion system has a structure of using a rotary motor and rack and pinion in which the pinion is rotatably driven by the rotary motor, thus moving the rack forward and backward. The screw device has a structure in which a nut screw-engaged with a screw axis is driven forward and backward by driving of the rotary motor.
Meanwhile, the in-pipe inspection robot is not able to move along the pipes with the rack-and-pinion system and the ball screw device only. Therefore, there is preceding issue that it is necessary to separately develop a brake device which can be adhered to the pipes or released from the adhered state, while exerting repulsive force to the pipes opposite to a direction of advancement.
However, even when the preceding issue is addressed, there still remains an issue of impaired motion on curved portions of the pipe because the rack of the rack-and-pinion system, which is not flexible in lengthwise direction, is stuck at the curved portion of the pipe. Likewise, the ball screw device also has a shortcoming that it is not able to move on the curved portions of the pipes because the screw axis, which is not flexible, is stuck at the curved portions of the pipes.